The present invention relates generally to dynamic random access memories (DRAMs), and, more specifically, to improved arrangements for output buffers, protection circuits, semiconductor memory devices, type developing methods for such memory devices, layout methods and test methods which are particularly effective if applied to a dynamic RAM, although not limited thereto.
One example of a dynamic RAM (Random Access Memory) and its package mode are disclosed on pp. 55 to 57 and 15 to 24 of "Hitachi IC Memory Data Book" issued in June 1987 by Hitachi, Ltd.
In this previous dynamic RAM, which has plural package specifications, the lead frame for packaging a semiconductor substrate will have different optimum shapes for the individual shapes of the package. Thus, the bonding pads for coupling the lead frames and the semiconductor substrate accordingly have optimum layout positions different for the individual package shapes. As a result, in addition to the bit structures and the operation modes, a number of semiconductor substrates have previously had to be prepared corresponding to the different package shapes. This restricts the reduction in the cost for the dynamic RAM thereby blocking the efficient development of various types of DRAMs.